This invention relates generally to signal selection apparatus and more particularly, to a converter and digital channel selector device interconnected between a source measurement unit having a plurality of output terminal connectors and a probe station having a plurality of input probe terminal connectors for selectively connecting each one of the plurality of output terminal connectors of the source measurement unit to any corresponding one of the plurality of input probe terminal connectors, respectively.
As is generally known in the prior art, the input terminal connectors of signal probes are typically connected via BNC-type or TRIAC-type connectors to the output terminal connectors of a signal source/measuring device for applying or measuring at desired test locations on a wafer of a semiconductor integrated circuit device. These signal probes are provided with suitable probe tips so as to easily secure the signal probes to the number of desired locations. Such a signal source/measuring device is one which is commercially available from Hewlett Packard of Palo Alto, Calif. under their Model No. HP4145. The HP4145 device is a source measuring unit which is sometimes referred to as a Semiconductor Parameter Analyzer. This source measurement unit has now been recognized as a standard in the semiconductor industry to be used for performing DC measurements.
Specifically, the HP4145 device is equipped with four source measuring units and two voltage sources and has the capability of storing on a floppy disc the configuration of its output terminal connectors for a particular test measurement to be made. Accordingly, when the same test measurement is to be repeated at a time in the future this can be achieved by simply loading the stored program. Further, certain types of test measurements have become so common in the semiconductor technology that they have now also become standards and are thus quite frequently formed in the normal routine of measurements.
However, in the situations where the multiple probes on the same source measurement unit are used to obtain a number of different test measurements there is created the problem of requiring the user to disconnect the BNC-type or TRIAC-type connectors from each of the multiple probes and then re-connect the same connectors to a different one of the multiple probes in order to change the function of each of the probes without having to re-program the stored output terminal connector configuration of the source measuring unit. This problem arises due to the fact that these output terminal connectors of the source measurement unit as stored in the program will seldom correlate or match up with the input terminal connectors of the probes whose tips are secured to the desired test locations for each of the number of different test measurements to be performed at the wafer level of the semiconductor integrated circuit device.
It would therefore be desirable to provide a converter and digital channel selector device which allows a user to quickly and easily reassign the function of the multiple probes coupled to the output terminal connectors of the same source measurement unit. It would also be expedient to have this implemented by the user without requiring re-programming of the source measurement unit or swapping of the terminal connectors.